U.S. wildlife officials say they will not renew licenses for four hydroelectric dams in California unless steps are taken to help imperiled wild salmon.

Federal wildlife agencies say the owner of the dams along the Klamath River must provide a way in which the salmon can reach their upriver spawning grounds. The salmon's passage has been blocked for nearly a century by the four hydroelectric facilities, The Los Angeles Times reported Thursday.

The owner of the dams, PacifiCorp of Portland, Ore., must now decide whether to spend as much as $175 million to build large fish ladders or abandon the dams.

The U.S. Fish and Wildlife Service, National Marine Fisheries Service and other federal agencies issued the demand after PacifiCorp filed an application to renew its operating licenses.

Copyright 2006 by United Press International